The objective of this research program is to elucidate the chemistry of metal ions coordinated to macrocyclic tetradentate ligands. The emphasis of the research program will be on the mechanisms of stoichiometrically simple chemical reactions. There will be three major thrusts of this research program: (1) The investigation of the physical properties and the chemical reactivity of cobalt(III)-alkyl moieties in complexes containing ligand systems with varying degrees of unsaturation; (2) a search for variations in chemical reactivity which depend on the extend and kind (conjugated, alpha-diamine, unconjugated, etc.) of macrocyclic ligand unsaturation; and (3) the continued investigation of the fundamental details of electron transfer reactions. A prevailing philosophy in much of this work will be to search for patterns or trends in reactivity in the reactions of simple synthetic complexes which contain certain of the structural features of prosthetic groups in metallo enzymes; items (1) and (2) above are clearly examples of this approach.